1. Field of the Invention
The present invention relates to binoculars having an image stabilizing function configured to reduce (or correct) image vibrations caused by hand blurs.
2. Description of the Related Art
Usually, a user manually holds binoculars in using the binoculars. Thus, an image stabilizing function configured to reduce image vibrations caused by hand blurs can improve the usability of the binoculars when the image stabilizing function is installed in the binoculars. The image stabilizing function of the binoculars is implemented by moving, through an actuator, parts of left and right optical systems orthogonal to an optical axis so that the image vibrations caused by the vibrations of the binoculars can be cancelled or reduced.
In the binoculars, a pair of similarly configured optical systems are arranged on the left side and the right side, and optical images formed by the left and right optical systems are simultaneously observed by both eyes. It is thus necessary to simultaneously stabilize images in the left and right optical systems.
Japanese Patent Laid-Open Nos. (“JPs”) 10-020213 and 10-301035 disclose binoculars configured to guide a lens holder configured to integrally hold left and right image stabilizing lenses, in two directions orthogonal to the optical axis by inserting a guide shaft held by one of the lens holder and the base member into a hole formed in the other of the lens holder and the base member.
However, in the guide structure for the lens holder in the binoculars disclosed in JPs 10-020213 and 10-301035, the lens holder displaces in the optical axis direction due to a gap between the guide shaft and the hole. In particular, when the lens holder that holds the left and right image vibrating lenses displaces oblique to or inclines relative to the optical axis direction, the focuses and sizes of the left and right optical images formed by the left and right optical systems become different, causing a sense of discomfort to a user who is observing these images with his both eyes.
In addition, a sliding friction occurs between the guide shaft and the hole, and causes driving resistance that is disadvantageous to fine driving of the lens holder by the actuator.